The video has become an online sensation with over 500,000 views in a week.

Double eggs are "extremely rare", according to Douglas Russell from the Natural History Museum, and almost never occur in supermarket-bought eggs.

Writing in The New Scientist, he suggested that the most likely reason for the double eggs were "that the normal rhythmic muscular action, or peristalsis, that moves a developing egg down the oviduct malfunctions in some way."